It is known that polyethylene oxides and other polyalkylene oxides (referred to collectively hereinafter as "polyethylene oxide") have a sensitizing effect when they are added to silver halide photographic photosensitive materials, for instance U.S. Pat. Nos. 2,716,062 and 2,784,091 and the literature references cited therein. It is stated in those disclosures that a sensitizing effect is seen from adding polyethylen, oxide derivatives of a molecular weight at least 300 silver halide photographic photosensitive materials.
This property of polyethylene oxide has bee considerable interest to photographic technologists, and many reports have been published in connection with this subject. Much of this research has been summarized on pages 424-426 of The Theory of the Photographic Process, fourth edition, edited by T. H. James, published by Macmillan, 1977. According to this work, the sensitizing effect of polyethylene oxides is thought to be a development accelerating action since in a series of developments with different development times the maximum attainable speed is unchanged but the development time for obtaining the highest attainable speed becomes shorter. Moreover, in connection with the development accelerating effect of polyethylene oxides it has been pointed out by Van Veelan et al. and by Kumai's research group that the development accelerating effect is enhanced by the presence of bromide ion. At least the three explanations indicated below have been put forward as to the cause of this effect, but no clear conclusions have been reached:
(i) the polyethylene oxide molecules are adsorbed on the silver halide grains and have an effect of material transfer in the vicinity of the silver halide grains, such as the transfer of the developing agent or the development inhibiting substances which is formed as a result of development; PA0 (ii) the hydrophilicity of a gelatin layer in which polyethylene oxide molecules are adsorbed on the silver halide grains is raised; and PA0 (iii) the polyethylene oxide molecules associate with the bromide ions in solution. PA0 (a) polyethylene oxide is highly water soluble and so if the acceleration of development in a specified layer among a plurality of silver halide emulsion layers is to be carried out, diffusion into other layers takes place and there is inevitably a marked effect in the silver halide emulsion layers other than the intended layer. The effect of the polyethylene oxide on each silver halide emulsion layer varies according to the grain size and halogen composition of the silver halide emulsion in each layer, differences in the adsorbed materials such as spectrally sensitizing dyes in each layer and the extent of chemical sensitization of each layer. Consequently, very complicated techniques are required to obtain the desired effect by the addition of polyethylene oxide; and PA0 (b) if the molecular weight is increased in order to lower the hydrophilicity of the polyethylene oxide, its adsorption on silver halide grains is increased. This has an adverse effect on the state of adsorption of spectrally sensitizing dyes etc. on the silver halide grains and, depending on the particular conditions, it can lead to aggregation of the silver halide grains or colloidal silver grains. PA0 (1) A silver halide photographic photosensitive material comprising a support, having thereon at least one silver halide photosensitive emulsion layer, wherein a polymer which can be represented by general formula (I) shown below is included in at least one of the structural layers of the photographic photosensitive material: ##STR2## PA0 (2) A silver halide photographic photosensitive material comprising a support, having thereon at least one silver halide photosensitive emulsion layer, wherein a polyurethane compound obtained by reacting dialcohol (C), polyethylene glycol (D) and diisocyanate (E) is included in at least one of the structural layers of the photographic photosensitive material. PA0 (3) A silver halide photographic photosensitive material comprising a support, having thereon at least one silver halide photosensitive emulsion layer, wherein a polyester compound obtained by reacting dialcohol (C), polyethylene glycol (D) and dicarboxylic acid or derivative thereof (F) is included in at least one of the structural layers of the photographic photosensitive material.
On the other hand, the inventors have discovered on investigating the applicability of the aforementioned development accelerating effect due to polyethylene oxide to silver halide multi-layer color photographic photosensitive materials that there are problems such as those indicated below:
The inclusion of polyethylene oxide as a partial structure in polymer particles, such as latex particles for example, in order to prevent diffusion in silver halide multi-layer color photographic photosensitive materials has been considered as one means of resolving these problems. On carrying out an investigation in connection with this objective the findings indicated below have now been discovered in connection with the use of latexes which have a polyethylene oxide chain as a partial structure in a silver halide photographic photosensitive material. Thus, it is disclosed in JP-B No. 1-18408 that the film properties such as dimensional stability for example and the anti-static effect can be improved by adding a latex which contains polyethylene oxide chains to a photosensitive material. (The term "JP-B" as used herein means an "examined Japanese patent publication".) It is disclosed in JP-A No. 61-62031 that the covering power of a silver halide emulsion can be improved by means of a latex which contains polyethylene oxide chains. (The term "JP-A" as used herein means an "unexamined published Japanese patent application".) The covering power according to that specification is defined as the value obtained by dividing the optical density by the number of grams of developed silver per unit area and this is not directly related to the development accelerating effect due to polyethylene oxide mentioned earlier.
Inventions in which latexes which contain polyethylene oxide chains are used as media in which hydrophobic substances such as various dye forming couplers are dispersed in silver halide photographic photosensitive materials have been disclosed in JP-B No. 64-3250 and JP-A No. 64-052136. In spite of the wide investigation, there is virtually no disclosure in these specifications of development accelerating effects with latexes which contain polyethylene oxide chains. The polyethylene oxide chains in the latex particles are adsorbed rather weakly on silver halide grains when compared with normal polyethylene oxide, and so the possibility that they have no development accelerating effect cannot be denied.
Thus, when the inventors started their investigation of methods of capturing iodide ions in a silver halide multi-layer color photographic photosensitive materials in a specified layer of the said photosensitive material, it was not clear whether polyethylene oxide was essentially effective for capturing iodide ions. Moreover, it was not clear at all that it would exhibit a development accelerating effect in cases where the polyethylene oxide was included as part of the structure of a macromolecular polymer which was essentially insoluble in water for fixing the polyethylene oxide in a specified layer in a silver halide multilayer color photographic photosensitive material.
As a result of a detailed investigation in connection with this objective, the inventors had shown that the acceleration of development in a specified layer among a plurality of silver halide emulsion layers was possible and that the effect on the photographic speed of the other layers was slight immediately after the manufacture of a photosensitive material when a latex which contained polyethylene oxide chains, as disclosed in JP-B No. 1-18408 for example, was used. However, it was also shown at the same time that this technique was unsuitable for use in photographic photosensitive materials because there was an effect on the photographic performance of the silver halide emulsion layers other than the target layer when the photographic material had been stored and aged.
The above mentioned problem was especially pronounced when the latex which contained polyethylene oxide chains was used in large quantities with a view to greater regulation of development acceleration. Consequently, the development of a latex which contains polyethylene oxide chains for photographic speed adjustment purposes with which there is essentially no change in photographic speed of the other layers even after ageing and storage is clearly desirable.